Finally GIMP 2.7.3 (unstable) has been released and ready to test, the most visible changes in this release are full single-window mode just like Photoshop which run on Windows, other enhancements contained on GIMP 2.7.3 are :

Support Layer Groups

Program administration

Enhancements in order to ‘on canvas’ textual content modifying

Addition of a ‘Lock Content’ switch in order to Levels,Channels and Path dialogs.

‘Rule of fifths’ crop guide overlay.

Install GIMP 2.7.3 in Ubuntu via PPA

To Install Ubuntu 9.10 as well as Ubuntu 11.04 via PPA, you can include this ’ppa:matthaeus123/mrw-gimp-svn’ to your Repository. This particular PPA isn't officially provide by GIMP. So, you should be thought about unstable.

To install GIMP 2.7.3 open a terminal window (press Ctrl+Alt+T) and copy+paste the following line:

If you have GIMP Installed in your ubuntu before, just add the PPA and upgrade GIMP using the Ubuntu Software Center or the Update Manager.Download GIMP 2.7.3 via FTP
You can also download GIMP 2.7.3 directly via GIMP FTP bellow :